Investigation of a new phase in Cu-containing Fe-Ni alloy for corrosion resistance behavior

ABSTRACT

In order to recognize the mechanisms of corrosion resistance in Cu-containing Fe-Ni alloys, two experimental composition 39.0Ni-57.1Fe-3.9Cu and 39.4Ni-57.7Fe-2.9Cu (at.-%) were designed according to the double-cluster model. The corrosion resistance measurements indicated that the alloy 39.0Ni-57.1Fe-3.9Cu possessed equal corrosion resistance to conventional steels 304 while the corrosion resistance of 39.4Ni-57.7Fe-2.9Cu was deteriorated by a new secondary precipitate phase. Observation by transmission electron microscopy and energy dispersive X-ray spectrometer showed evidence of the new phase in alloy 39.4Ni-57.7Fe-2.9Cu which having a crystal structure in a face-centered-cubic (FCC) symmetry and owning parameter a = 8.2Å. A possible atomic composition was confirmed to be 16.8Ni-74.9Fe-8.3Cu.

KEYWORDS:

• Cu-containing Fe-Ni
• corrosion-resistant alloy
• new phase and double-cluster structure model

Funding

This work is supported by the National Natural Science Foundation of China (No. 11174044), the National Basic Research Program of China (No. 2011CB936002), the National Natural Science Foundation of China (No. 51178076) and the Fundamental Research Funds for the Central Universities (No. DUT14LK17).